1. The Field of the Invention
This invention concerns improvements in and relating to fuel transportation, particularly but not exclusively relating to enriched nuclear fuels.
2. The Relevant Technology
Nuclear fuels, such as enriched uranium or mixed oxide forms, frequently need to be transported between sites, for instance the enrichment site and the fuel rod production site. The fuel is normally in the form of pellets or powder at this stage. International standards apply, requiring certain levels of thermal insulation and structural strength. A major concern is criticality control. The mass of enriched fuel within the transport container must be strictly limited to ensure that a criticality event does not occur. This single requirement places a stringent limit on the volume of fuel which can be transported in any given volume of a transport container. In this regard, the transportation of nuclear fuel differs significantly from transportation of other radioactive materials. Radioactive waste is of a far lower enrichment, thus facilitating transport of greater volumes in proximity with one another. In assembled fuel rods on the other hand, the volume of fuel when compared with the overall fuel rod and supporting structure volume is very low.